| Author | Message | ||
     Henrik |
I want to mount a Nissin caliper on the S2. The stock master cylinder and braided steel line were used with DOT 5 fluid. The Nissin caliper was used with DOT 4 fluid. What are your suggestions: I can either clean the caliper and use DOT 5 or clean master cylinder and brake line and use DOT 4. I guess I'd prefer DOT 4 fluid for the higher boiling point. but what will it take to clean the DOT 5 out of the stock parts, and will the stock rubber seals, line "liner" etc. be ok with the cleaner and DOT 4 fluid? Henrik | ||
| Jim_witt |
Henrik, Check this site out for the brake fluid switching question. After reading "everything there" it doesn't answer your question. Anyway, I just rebuilt my brakes last week and the service manual says to clean everything with denatured alcohol (page C-18 in my 98 S3T book). -JW:  (Message edited by jim_witt on May 01, 2003) | ||
| Henrik |
Thanks Jim; I guess I got the boiling point thing wrong. The "spongyness" I guess is why DOT4 is used in most modern performance brakes - and why DOT4 would be my choice. So do you think denatured alcohol will be enough to clean the DOT5 out of the old system? I seem to remember someone using much nastier stuff to clean a brake system before switching. Thanks again Henrik | ||
| Jim_witt |
Henrik, Dunno, they did say NOT to use mineral-base cleaning solvents, such as gas or paint thinner because they cause deterioration of the rubber parts. Since I rebuilt everything, I simply followed the directions ... denatured alcohol. -JW:>  | ||
| Henrik |
I did some further searching and made a few calls: 1) there doesn't seem to be any concrete wisdom about switching from silicone based fluid (DOT5) to glycol based (DOT 3 & 4) 2) Everyone I talked to agreed that a thorough cleaning would be necessary. 3) No one could give specifics about what to use for cleaning - except, as Jim pointed out (thanks), do not use anything too harsh. 4) Both Spiegler and Galfer brakes agreed that cleaning with denatured alcohol would *probably* be enough, and that disassembling the master cylinder for cleaning would be a good idea. 5) I have a call out to Castrol for more info and will report if I hear back. Henrik | ||
| Steveshakeshaft |
FWIW, about two years ago I changed the fluid on mine from DOT5 using DOT5.1. I subsequently found out that in fact 5.1 is "really" an upgrade to DOT4 NOT DOT5. Two years later and everything still seems fine. I guessed that having done the "damage" by putting the wrong fluid in there that I was wasting my time changing back. Just my 2 cents, but what I'm really saying is that sometimes we can worry just a little to much? For sure, I would much rather have the wrong brake fluid than an incompatible solvent in there rotting the seals! Regards Steve steve_s@ukbeg.com http://ukbeg.com | ||
| Henrik |
Good to know Steve  Thanks Henrik | ||
| Reepicheep |
Henrik... Had a long post typed up, checked some resources, deleted the whole mess as wrong. Never mind. Here is one of the better links I found... http://www.mrtrally.com.au/forums/topic.asp?TOPIC_ID=403 You will need a good flush, but it looks like the 5.1 will be seal friendly. Steve... as the dot 5.1 won't hurt your seals, you did not damage anything, just think of it as an extended flush. | ||
| Henrik |
That was a very informative link. Thanks Bill.  Henrik | ||
| Henrik |
I especially found this to be useful in my search: This is the ratio of master cylinder bore area and caliper piston bore area. (MC-master cylinder) A larger MC results in... > less pedal travel > a firmer pedal > less hydraulic advantage A smaller MC results in... > more pedal travel > a softer pedal > more hydraulic advantage Larger caliper piston area results in... > more pedal travel > a softer pedal > more hydraulic advantage Smaller caliper piston area results in... > less pedal travel > a firmer pedal > less hydraulic advantage Henrik | ||
| Henrik |
The above explains why I'd prefer a 1/2" master instead of the 5/8" stock S2 master. I did find out about the DOT4/5 switch. Reliable sources feel that if DOT 5 brake parts are thoroughly cleaned with denatured alcohol, it shouldn't be a problem going to DOT 4 fluid. I'm happy I found out, however incompatibilities between the different new/old brake part prevent me from putting it all together. So far no luck finding a solution: The stock master will not provide the braking power I'd like. The 1/2" master I have can't be drilled up - not enough metal. The stock line will not fit the Nissin caliper - the fitting is too big to fit into the "holding" slot in the caliper. The late model line I have will not fit the stock master - the fittings are rotated 90° to where they should be and the top fitting is too small: it takes a 10 mm bolt, the stock master requires an 11 mm bolt. No one makes a 1/2" master for 1" bars. So these are the remaining options: 1) buy a custom made brake line to make the stock master work with the Nissin caliper = less braking power. 2) cut/weld a short piece of 7/8" bar into the stock bar for the new style master, retaining the stock switchgear/throttle grip = better braking but need a welder ... 3) go whole hog and change bars to 7/8" and go with all new controls and switchgear = much cash, work and wiring ... not happening right now. Henrik | ||
| Road_thing |
4) Buy a 1/2" master and ream the 7/8" hole to 1". r-t | ||
| Blake |
I saw just recently in RRW or it could have been Cycle World a company advertising brake lines with threaded ends to eliminate the banjo bolt at the master cylinder. They claimed to be able to fit a line to any system. Would that help? | ||
| Henrik |
r-t wrote: 4) Buy a 1/2" master and ream the 7/8" hole to 1". You may have missed it - but I did look into that. The 1/2" master I have doesn't have enough metal to be reamed out. Less than 1 mm before you get into the clamping bolt holes. Some other brand master may work, but the Nissin that comes stock on Buells will not. Thanks though Blake, it might, but again, not really. I'm sure I can have a line made that will allow me to use the stock master with the new Nissin caliper, and that combination with better pads and DOT4 fluid will likely be an improvement. I'm however hesitant to spend $$ for a less than optimal set-up (1/2" master would be best with a single caliper system) Of course I could sell a couple of vital organs and buy a full Brembo dual disk kit ... I wish - too much wear on my organs already ![:]](http://www.badweatherbikers.com/buell/clipart/ohwell.gif) Henrik | ||
| Henrik |
OK, this is getting frustrating; I decided to just get a brake line that would fit the Nissin caliper and the stock HD style master .... started calling around, and apparently brake line makers put 12 mm banjos on HD lines - of course my master takes an 11 mm bolt and banjo. Any of you have a stock S2/HD master and banjo bolt you can measure for me? Henrik |
